I have not worked with Software Raid before, only with basic Hardware raid, 2 drives where the system is mirrored.

I have an existing system running Ver. 7.3 on a 500GB drive setup as a Gateway with Plex Media Server.
I have multiple drives mounted with media on them, a combination of 500GB, 1TB and 2TB drives.
My system is basically like this:
1. 1x 500GB - Main Drive with OS.
2. 1x 500GB - Used as temporary storage for file renaming and editing.
3. 10x Media drives, 500GB, 1TB and 2TB drives

I would like to create a Software Raid 5 or 6 with 8x 2TB drives to store all my media on - I have 8x 2TB drives that are not installed in the system.

Here is my questions...
1. Can i install the Software Raid on my existing system?
2. Can i keep the OS on the existing 500GB drive and have the raid separate, i would like to spin the Raid drive down when they are not in use?
3. Once i have the 8x 2TB drives as a Software Raid 5, can i add two 2TB drives to the Raid drive? The plan is once the data is transferred to the Raid, i shall have some spare 2TB drives.

Accepted Answer

I had to do a clean install, for some reason ClearOS did not see my 2nd NIC after i changed the drives out with a set of 2TB drives???
It kept going to the recovery page and i could see the NIC is not initialized.

So i am busy building the Raid6 array - another 1618 min., it is mounted and once i have transferred drive 9 and 10 data to the raid array, i shall add them to the array as well.

Thank you for everyone that assisted, it was a great help for a Software Raid Newby

Accepted Answer

If i reate a raid with 8 drives, /dev/sdb1 to /dev/sdi1,with 2 other 2TB drives with data on that i shall transfer to the raid once it is created.
When i remove the 2 non-raid drives and place 2 other drives in their location, will this not have the potencial to break the raid?
Is it not possable that the new non-raid drive might have a location of /dev/sde1 that is in the range of the raid i created.

Accepted Answer

To spin down drives check out the hdparm command where you can set a spin down time. Be careful if you also use smartmontools as this can stop the drives from spinning down. You may also want to use the noatime switch for the drives in /etc/fstab.

Accepted Answer

Sure you can do that. Raids can be created at any time. First you need to find the folders where most of you data is. In an ideal case it is mainly /var and you can just move all your data from your 500GB main drive to the raid. Considering Raid 5 and 6 you can add drives at any time, as long as they have the same size. I should mention that if they are not from the same brand and type (even the size is the same), they might be some bytes off from one another. For a Raid 5/6 the partition on each drive needs to be exactly the same. In case they vary chose the size of the smallest drive.

In case you data is mainly in e.g. /var, you can just make a raid, transfer your data and mount it in fstab at /var (this is how I do it). Remember that it might be good to boot from a live CD/DVD/USB stick to avoid data corruption while you transfer the data between drives.

In case it is spread over multiple folders the following How To is useful to read: